1 (***********************************************************************)
5 (* Kim Nguyen, LRI UMR8623 *)
6 (* Université Paris-Sud & CNRS *)
8 (* Copyright 2010-2013 Université Paris-Sud and Centre National de la *)
9 (* Recherche Scientifique. All rights reserved. This file is *)
10 (* distributed under the terms of the GNU Lesser General Public *)
11 (* License, with the special exception on linking described in file *)
14 (***********************************************************************)
17 Time-stamp: <Last modified on 2013-03-11 00:14:28 CET by Kim Nguyen>
24 type predicate = | First_child
31 | Is of (Tree.Common.NodeKind.t)
35 let is_move p = match p with
36 | First_child | Next_sibling
37 | Parent | Previous_sibling | Stay -> true
41 type atom = predicate * bool * State.t
43 module Atom : (Formula.ATOM with type data = atom) =
49 let equal n1 n2 = n1 = n2
50 let hash n = Hashtbl.hash n
53 include Hcons.Make(Node)
56 let p, b, q = a.node in
57 if not b then fprintf ppf "%s" Pretty.lnot;
59 | First_child -> fprintf ppf "FC(%a)" State.print q
60 | Next_sibling -> fprintf ppf "NS(%a)" State.print q
61 | Parent -> fprintf ppf "FC%s(%a)" Pretty.inverse State.print q
62 | Previous_sibling -> fprintf ppf "NS%s(%a)" Pretty.inverse State.print q
63 | Stay -> fprintf ppf "%s(%a)" Pretty.epsilon State.print q
64 | Is_first_child -> fprintf ppf "FC%s?" Pretty.inverse
65 | Is_next_sibling -> fprintf ppf "NS%s?" Pretty.inverse
66 | Is k -> fprintf ppf "is-%a?" Tree.Common.NodeKind.print k
67 | Has_first_child -> fprintf ppf "FC?"
68 | Has_next_sibling -> fprintf ppf "NS?"
71 let p, b, q = a.node in
79 include Formula.Make(Atom)
80 open Tree.Common.NodeKind
81 let mk_atom a b c = atom_ (Atom.make (a,b,c))
82 let mk_kind k = mk_atom (Is k) true State.dummy
84 (mk_atom Has_first_child true State.dummy)
86 let has_next_sibling =
87 (mk_atom Has_next_sibling true State.dummy)
90 (mk_atom Is_first_child true State.dummy)
93 (mk_atom Is_next_sibling true State.dummy)
96 (mk_atom (Is Attribute) true State.dummy)
99 (mk_atom (Is Element) true State.dummy)
101 let is_processing_instruction =
102 (mk_atom (Is ProcessingInstruction) true State.dummy)
105 (mk_atom (Is Comment) true State.dummy)
109 (mk_atom First_child true q)
114 (mk_atom Next_sibling true q)
119 (mk_atom Parent true q)
122 let previous_sibling q =
124 (mk_atom Previous_sibling true q)
128 (mk_atom Stay true q)
133 | Formula.Atom a -> let _, _, q = Atom.node a in
134 if q != State.dummy then StateSet.add q acc else acc
142 mutable states : StateSet.t;
143 mutable selection_states: StateSet.t;
144 transitions: (State.t, (QNameSet.t*SFormula.t) list) Hashtbl.t;
147 let next = Uid.make_maker ()
149 let create () = { id = next ();
150 states = StateSet.empty;
151 selection_states = StateSet.empty;
152 transitions = Hashtbl.create 17;
156 let get_trans a states tag =
157 StateSet.fold (fun q acc0 ->
159 let trs = Hashtbl.find a.transitions q in
160 List.fold_left (fun acc1 (labs, phi) ->
161 if QNameSet.mem tag labs then (q,phi)::acc1 else acc1) acc0 trs
162 with Not_found -> acc0
166 [add_trans a q labels f] adds a transition [(q,labels) -> f] to the
167 automaton [a] but ensures that transitions remains pairwise disjoint
170 let add_trans a q s f =
171 let trs = try Hashtbl.find a.transitions q with Not_found -> [] in
173 List.fold_left (fun (acup, atrs) (labs, phi) ->
174 let lab1 = QNameSet.inter labs s in
175 let lab2 = QNameSet.diff labs s in
177 if QNameSet.is_empty lab1 then []
178 else [ (lab1, SFormula.or_ phi f) ]
181 if QNameSet.is_empty lab2 then []
182 else [ (lab2, SFormula.or_ phi f) ]
184 (QNameSet.union acup labs, tr1@ tr2 @ atrs)
185 ) (QNameSet.empty, []) trs
187 let rem = QNameSet.diff s cup in
188 let ntrs = if QNameSet.is_empty rem then ntrs
189 else (rem, f) :: ntrs
191 Hashtbl.replace a.transitions q ntrs
193 let _pr_buff = Buffer.create 50
194 let _str_fmt = formatter_of_buffer _pr_buff
195 let _flush_str_fmt () = pp_print_flush _str_fmt ();
196 let s = Buffer.contents _pr_buff in
197 Buffer.clear _pr_buff; s
201 "\nInternal UID: %i@\n\
203 Selection states: %a@\n\
204 Alternating transitions:@\n"
206 StateSet.print a.states
207 StateSet.print a.selection_states;
210 (fun q t acc -> List.fold_left (fun acc (s , f) -> (q,s,f)::acc) acc t)
214 let sorted_trs = List.stable_sort (fun (q1, s1, _) (q2, s2, _) ->
215 let c = State.compare q1 q2 in - (if c == 0 then QNameSet.compare s1 s2 else c))
218 let _ = _flush_str_fmt () in
219 let strs_strings, max_pre, max_all = List.fold_left (fun (accl, accp, acca) (q, s, f) ->
220 let s1 = State.print _str_fmt q; _flush_str_fmt () in
221 let s2 = QNameSet.print _str_fmt s; _flush_str_fmt () in
222 let s3 = SFormula.print _str_fmt f; _flush_str_fmt () in
223 let pre = Pretty.length s1 + Pretty.length s2 in
224 let all = Pretty.length s3 in
225 ( (q, s1, s2, s3) :: accl, max accp pre, max acca all)
226 ) ([], 0, 0) sorted_trs
228 let line = Pretty.line (max_all + max_pre + 6) in
229 let prev_q = ref State.dummy in
230 List.iter (fun (q, s1, s2, s3) ->
231 if !prev_q != q && !prev_q != State.dummy then fprintf fmt " %s\n%!" line;
233 fprintf fmt " %s, %s" s1 s2;
234 fprintf fmt "%s" (Pretty.padding (max_pre - Pretty.length s1 - Pretty.length s2));
235 fprintf fmt " %s %s@\n%!" Pretty.right_arrow s3;
237 fprintf fmt " %s\n%!" line
240 [complete transitions a] ensures that for each state q
241 and each symbols s in the alphabet, a transition q, s exists.
242 (adding q, s -> F when necessary).
245 let complete_transitions a =
246 StateSet.iter (fun q ->
247 let qtrans = Hashtbl.find a.transitions q in
249 List.fold_left (fun rem (labels, _) ->
250 QNameSet.diff rem labels) QNameSet.any qtrans
253 if QNameSet.is_empty rem then qtrans
255 (rem, SFormula.false_) :: qtrans
257 Hashtbl.replace a.transitions q nqtrans
260 let cleanup_states a =
261 let memo = ref StateSet.empty in
263 if not (StateSet.mem q !memo) then begin
264 memo := StateSet.add q !memo;
265 let trs = try Hashtbl.find a.transitions q with Not_found -> [] in
266 List.iter (fun (_, phi) ->
267 StateSet.iter loop (SFormula.get_states phi)) trs
270 StateSet.iter loop a.selection_states;
271 let unused = StateSet.diff a.states !memo in
272 eprintf "Unused states %a\n%!" StateSet.print unused;
273 StateSet.iter (fun q -> Hashtbl.remove a.transitions q) unused;
276 (* [normalize_negations a] removes negative atoms in the formula
277 complementing the sub-automaton in the negative states.
278 [TODO check the meaning of negative upward arrows]
281 let normalize_negations auto =
282 eprintf "Automaton before normalize_trans:\n";
283 print err_formatter auto;
284 eprintf "--------------------\n%!";
286 let memo_state = Hashtbl.create 17 in
287 let todo = Queue.create () in
289 match SFormula.expr f with
290 Formula.True | Formula.False -> if b then f else SFormula.not_ f
291 | Formula.Or(f1, f2) -> (if b then SFormula.or_ else SFormula.and_)(flip b f1) (flip b f2)
292 | Formula.And(f1, f2) -> (if b then SFormula.and_ else SFormula.or_)(flip b f1) (flip b f2)
293 | Formula.Atom(a) -> begin
294 let l, b', q = Atom.node a in
295 if q == State.dummy then if b then f else SFormula.not_ f
297 if b == b' then begin
298 (* a appears positively, either no negation or double negation *)
299 if not (Hashtbl.mem memo_state (q,b)) then Queue.add (q,true) todo;
300 SFormula.atom_ (Atom.make (l, true, q))
302 (* need to reverse the atom
303 either we have a positive state deep below a negation
304 or we have a negative state in a positive formula
305 b' = sign of the state
306 b = sign of the enclosing formula
310 (* does the inverted state of q exist ? *)
311 Hashtbl.find memo_state (q, false)
314 (* create a new state and add it to the todo queue *)
315 let nq = State.make () in
316 auto.states <- StateSet.add nq auto.states;
317 Hashtbl.add memo_state (q, false) nq;
318 Queue.add (q, false) todo; nq
320 SFormula.atom_ (Atom.make (l, true, not_q))
324 (* states that are not reachable from a selection stat are not interesting *)
325 StateSet.iter (fun q -> Queue.add (q, true) todo) auto.selection_states;
327 while not (Queue.is_empty todo) do
328 let (q, b) as key = Queue.pop todo in
331 Hashtbl.find memo_state key
334 let nq = if b then q else
335 let nq = State.make () in
336 auto.states <- StateSet.add nq auto.states;
339 Hashtbl.add memo_state key nq; nq
341 let trans = Hashtbl.find auto.transitions q in
342 let trans' = List.map (fun (lab, f) -> lab, flip b f) trans in
343 Hashtbl.replace auto.transitions q' trans';